WASHINGTON (AP) - America’s cities are still growing, with the population boom fueled by people picking up and moving to find jobs in energy production across the oil- and gas-rich areas west of the Mississippi River.

New 2013 census information released Thursday shows that cities are the fastest-growing parts of the United States, and a majority of the metro areas showing that growth are located in or near the oil- and gas-rich fields of the Great Plains and Mountain West.

Neighboring cities Odessa and Midland, Texas, show up as the second and third fastest-growing metro areas in the country. Sara Higgins, the Midland public information officer, has a simple explanation: oil. “They’re coming here to work,” Higgins said.

Energy production is one of the fastest-growing industries in the United States, the Census Bureau said. The boom in the U.S. follows the use of new technologies, such as hydraulic fracturing and horizontal drilling, to tap oil and gas reserves.

“Mining, quarrying, and oil and gas extraction industries were the most rapidly growing part of our nation’s economy over the last several years,” Census Bureau Director John H Thompson said.

According to its data, revenue for mining, quarrying, and oil and gas extraction grew 34.2 percent to $555.2 billion from 2007 to 2012. It also was among the fastest growers in employment as the number of employees rose 23.3 percent to 903,641.

The population boom does come with some challenges, said Andrea Goodson, the public information coordinator in Odessa, including the need for quick improvements to city infrastructure and housing to deal with the influx of new people.

With the population increase “comes a unique set of circumstances to deal with, so it’s been a double-edged sword,” Goodson said.

While energy exploration is drawing people to the Great Plains and Mountain West, Florida is still the one of the top destinations in the country, as it shows up again and again in census data for population growth.

Fueled by an increasing number of retirees, the fastest-growing metro area in the country was The Villages, boasting a 5.2 percent increase in population between 2012 and 2013. Its surrounding county, Sumter County, also shows up as one of the fastest-growing counties in the country with a 5.2 percent increase during the time period.

Gary Lester, vice president for community relations at The Villages, said Friday it draws retirees and people from all 50 states to their communities, which were designed with the influx of people in mind. “It’s all about the active lifestyle we offer,” Lester said.

- Metro areas grew faster than the United States as a whole (0.9 percent compared with 0.7 percent).

- Metro areas with populations of 1 million or more in 2012 grew 1.0 percent, compared with 0.5 percent for those with populations of less than 250,000.

-The nation’s fastest-growing city by number of people was Houston, which gained 138,000 people between 2012 and 2013. The surrounding county, Harris Country, also showed the fastest numerical population increase at almost 83,000 people.

-New York was the nation’s largest metropolitan area, with 19.9 million residents.

-Los Angeles was once again the nation’s most populous county, with a population of more than 10 million.

The census estimates are based on local records of births and deaths, Internal Revenue Service records of people moving within the United States and census statistics on immigrants.